Quad Small Form-factor Pluggable (QSFP) devices are compact, hot-pluggable transceivers used for data communications applications. These transceivers interface networking hardware to a fiber optic cable.
QSFP is an industry format jointly developed and supported by many network component vendors, allowing among others data rates from 4×10 Gbit/s. The format specification is evolving to enable higher data rates, and of May 2013, the highest possible rate is 4×28 Gbit/s, while the rate is in the process of continuous growth to higher rates.
For example, contemporary QSFP boards experience high insertions loss deviation in terms of Amplitude (in decibels (dB)) or power, versus signal frequency (in Mega Hertz). This results in non-linear behavior, when graphed.